Microcontrollers Data Sheet

MC68HC(7)08KH12 — Rev. 1.1 Advance Information
Freescale Semiconductor
249
17.4 Functional Operating Range
17.5 Thermal Characteristics
Characteristic Symbol Value Unit
Operating Temperature Range T
A
0 to 85 °C
Operating Voltage Range V
DD
4.0 to 5.5 V
Characteristic Symbol Value Unit
Thermal Resistance
QFP (64 Pins) θ
JA
70 °C/W
I/O Pin Power Dissipation P
I/O
User Determined W
Power Dissipation
(1)
P
D
P
D
= (I
DD
x V
DD
) + P
I/O
=
K/(T
J
+ 273 °C)
W
Constant
(2)
K
P
D
x (T
A
+ 273 °C)
+ P
D
2
× θ
JA
W/°C
Average Junction Temperature T
J
T
A
+ (P
D
× θ
JA
) °C
Maximum Junction Temperature T
JM
100 °C
NOTES
1. Power dissipation is a function of temperature.
2. K is a constant unique to the device. K can be determined for a known T
A
and measured
P
D.
With this value of K, P
D
and T
J
can be determined for any value of T
A
.